Related Experiment Video
Updated: Aug 12, 2026

Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays
Published on: February 4, 2021
The working stroke of myosin crossbridges
1Rosenstiel Center, Brandeis University, Waltham, Massachusetts 02254, USA.
Abstract:
Recent x-ray diffraction measurements of the axial periodicities of the actin and myosin filaments in contracting muscles show that they are stretched by small but significant amounts by the developed tension, so that at least one half, possibly more, of the observed compliance of a sarcomere must reside in the filaments themselves. This implies that the movement steps of a crossbridge deduced from quick-release experiments may be shorter than some previous estimates, necessitating at least two steps to account for current in vitro single-molecule measurements. Intensity measurements of the wider angle x-ray reflections also show some unexpected features.
Related Concept Videos
Cross-bridge Cycle
Overview of Myosin Structure and Function
Actin and Myosin in Muscle Contraction
ATP Synthase: Mechanism
Excitation-Contraction Coupling in Skeletal Muscles
When an action potential...
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...

